My boy has one and just "broke" a driveshaft. The one that connects the deck to the tractor.
I am not sure,by his description exactly what broke, but he said it would cost $500 for the shaft.
The model number of the tractor is 144-998-190(The 998 could be 993)
The model number of the deck is 150-993-190(The 150 could be 190, the 993 could be 998)
I wish I could see the damage but mower has been shopped.